# Precision and Accuracy Questions Objective: This laboratory exercise is intended to determine the relative accuracy and precision of several pieces of labo

Precision and Accuracy Questions Objective:
This laboratory exercise is intended to determine the relative accuracy and precision of several pieces of
laboratory glassware, to teach you basic laboratory techniques, and the importance of recording the
maximum number of significant figures in every measurement. Calculations and Results: (3 pts)
Show all calculations with units and report results to the correct number of significant
figures.
Mass and Density of water:
Show one calculation for the mass and density of water using your data. Indicate which trial and
piece of glassware was used. For example “graduated cylinder trial 1”
For each of the glassware types (graduated cylinder, pipette and burette):
Show the following calculations in the table below and record results in the “results table.
Absolute error
Average Density
Density Range
0.9045996667 0.093032
0.960535 –
0.866857
.0.093678
0.056903
0.951736
Burette
0.045896
..22
Pipette
0.9977666 0.001346
0.0033
GG7
Discussion and Conclusion: (2 pts)
RESULTS TABLE
Absolute
Glassware
Density
Range
Average
Density
Error
Cylinder
Burette
Pipette
Rank the types of glassware in order of least to most precise. DISCUSS in complete sentences
what data (numbers) led you to draw these conclusions.
Rank the types of glassware in order of least to most accurate. DISCUSS in complete sentences
what data (numbers) led you to draw these conclusions.
questions: (2 pts)
1. Sources of error. For each lab going forward, you will need to identify and discuss sources of
error. Answer the questions below to learn what types of error we are looking for and what
information to provide now and in the future each time you make a measurement.
a. How is the volume in a graduated cylinder measured? (What do you actually DO to
measure it?)
b. Given how it is measured, what causes variability in this measurement?
c. Does this error always cause a high or low value? Is the error random or systemic?
d. How does the error in this measurement effect the final result? (In this case, how does
a high/low value effect the calculated density, and then ultimately the conclusions you
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e. What, if anything, can you do to reduce this error?
2. Indicate how many significant figures are in each.
a. 1021.00
6
b. 34,700
3
C. 6.10 x 1021
d. 0.020000
3
3. Report 237.69 to 2 significant figures.
The largest gold nugget on record was found in 1872 in New South Wales, Australia, and weighed
93.3 kg. What was the volume of this nugget in cm and liters? The density of gold is 19.32 g/mL.
1 cm =
= 1 ml. Show all work using dimensional analysis with units cancellation.